<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>16-while循环</title>
</head>
<body>
  <script>
    //1.变量的起始值
    let i = 1
    //2.终止条件
    while (i <= 3) {
      document.write('循环三次 <br>')
      //3.变量的变化量
      i++
    }
  </script>
</body>
</html>